1. Field of the Invention
The present invention relates to a nonaqueous electrolyte battery and a nonaqueous electrolytic solution.
2. Description of the Related Art
Nonaqueous electrolytic secondary batteries of the type that uses, as a material for the battery's negative electrode, a lithium metal, a lithium alloy, a lithium compound such as a metal oxide capable of storing and releasing lithium ions, or a carbon material are expected to find application as high-energy density batteries. Much effort has been devoted to developing nonaqueous electrolyte batteries with larger capacities. Of the materials for the negative electrodes, the carbon materials ensure a long battery life and safety despite the reduced capacity of the carbon material-made negative electrodes when compared to the lithium-based electrodes. For this reason, lithium-ion batteries having for example a positive electrode made of a lithium-cobalt oxide and a negative electrode made of the carbon material are widely used as the power source of various mobile equipment.
The batteries with a negative electrode made of lithium metal or capable of storing and releasing lithium ions can achieve a high battery voltage. Thus, the energy density of these batteries can be more readily increased than those of the conventional primary and secondary batteries. Nevertheless, a demand still exists for batteries with even larger capacity and longer battery life.
In one study conducted to develop batteries to meet such demand, a special composition was used to serve as the electrolytic solution in a lithium-based nonaqueous electrolyte battery in the hope of increasing the discharge efficiency of the battery. The composition was prepared by dissolving electrolytes such as lithium perchlorate in a sulfone-based electrolytic solution such as DMSO2(Journal of Power Sources, 16 (1985) 193–204). However, even these lithium-based batteries using such an electrolytic solution failed to provide sufficient characteristics to meet the above-described demand for the battery.